Gonzalez spent Friday receiving treatment and did not take any swings or participate in the club's short workout at Sydney Cricket Ground.
"Adrian is good," Mattingly said Friday. "He won't hit today on the field. We're expecting him to go tomorrow. He won't be out [on the field] today. It's a pretty light day anyway. He hit in the cage. He feels all right. … He feels something there ... he's not 100 percent."
Gonzalez said he thought extensive sightseeing walking led to his stiff back and also believed he would be fine by Saturday night.
Mattingly has Gonzalez batting fourth in Saturday night's lineup.
Ken Gurnick is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.